[SPIR-V] Compiling with doubles may also implicitly enable Int64 capability (which may or may not be supported)

[Nielsbishere]

Description
When loading and adding a 64-bit float from a BAB it produces 64-bit int instructions as well, even though not used in the source.

Steps to Reproduce

typedef uint U32;
typedef float F32;

typedef double3 F64x3;
typedef float3 F32x3;

typedef uint4 U32x4;

static const U32 ResourceId_mask = (1 << 17) - 1;

struct TransformPreciseDouble {		//Stride 8, Length 24
	F64x3 pos;
};

struct TransformImprecise {			//Stride 4, Length 12
	F32x3 pos;		//Relative to the camera origin
};

enum EResourceBinding {
	EResourceBinding_ObjectTransformsLocal,
	EResourceBinding_ObjectTransformsGlobal,
    EResourceBinding_ObjectTransformsLocalRW
};

#ifdef __spirv__
    #define _binding(a, b, ...) [[vk::binding(a, b)]] __VA_ARGS__
	#define _vkBinding(a, b) [[vk::binding(a, b)]]
#else
    #define _binding(a, b, ...) __VA_ARGS__ : register(space##a)
	#define _vkBinding(a, b)
#endif

_vkBinding( 0, 2) cbuffer globals {	//Globals used during the entire frame for useful information such as frame id.

	U32 _frameId;					//Can loop back to 0 after U32_MAX!
	F32 _time;						//Time since launch of app
	F32 _deltaTime;					//deltaTime since last frame.
	U32 _swapchainCount;			//How many swapchains are present (will insert ids into appData)

	U32x4 _swapchains[8];			//Descriptors of swapchains: (Read, write)[2][8]

	//Up to 368 bytes of user data, useful for supplying constant per frame data.
	//Make sure to offset to make sure.

	U32x4 _appData[23];
};

U32 getAppData1u(U32 offset) { return offset >= 92 ? 0 : _appData[offset >> 2][offset & 3]; }

#define rwBufferUniform(i) _rwBuffer[i & ResourceId_mask]
#define bufferUniform(i) _buffer[i & ResourceId_mask]

_binding( 3, 1, ByteAddressBuffer _buffer[131072]);
_binding( 4, 1, RWByteAddressBuffer _rwBuffer[131072]);

template<typename T>
void setAtUniform(U32 resourceId, U32 id, T t) {
	rwBufferUniform(resourceId).Store<T>(id, t);
}

template<typename T>
T getAtUniform(U32 resourceId, U32 id) {
	return bufferUniform(resourceId).Load<T>(id);
}

U32 bufferBytesUniform(U32 resourceId) {
	U32 bytes;
	bufferUniform(resourceId).GetDimensions(bytes);
	return bytes;
}

[[oxc::stage("compute")]]
[[oxc::extension("I64", "F64")]]	//Loading F64 might incurr I64 instructions in spirv
[numthreads(256, 1, 1)]
void main(U32 i : SV_DispatchThreadID) {

	U32 objectTransformGlobal = getAppData1u(EResourceBinding_ObjectTransformsGlobal);

	U32 bytes = bufferBytesUniform(objectTransformGlobal);

	TransformImprecise result;

	{

		U32 elems = bytes / sizeof(TransformPreciseDouble);

		if(i + 1 >= elems)
			return;
			
		TransformPreciseDouble cam = getAtUniform<TransformPreciseDouble>(objectTransformGlobal, 0);
		TransformPreciseDouble obj = getAtUniform<TransformPreciseDouble>(objectTransformGlobal, i + 1);
		result.pos = (float3)(obj.pos - cam.pos);
	}

	U32 objectTransformLocal = getAppData1u(EResourceBinding_ObjectTransformsLocalRW);
	setAtUniform(objectTransformLocal, i + 1, result);
}

Turns into roughly:

Section has 20486 bytes.
 Showing offset #0 with size 20486
 File contents: (ascii)
 ; SPIR-V
; Version: 1.5
; Generator: Google spiregg; 0
; Bound: 138
; Schema: 0
               OpCapability Shader                  ; 0x00000014
               OpCapability Float64                 ; 0x0000001c
               OpCapability Int64                   ; 0x00000024
               OpMemoryModel Logical GLSL450        ; 0x0000002c
               OpEntryPoint GLCompute %1 "main" %gl_GlobalInvocationID %3 %4 %5     ; 0x00000038
               OpExecutionMode %1 LocalSize 256 1 1                                 ; 0x0000005c

               ; Annotations
               OpDecorate %gl_GlobalInvocationID BuiltIn GlobalInvocationId         ; 0x00000074
               OpDecorate %3 DescriptorSet 1                                        ; 0x00000084
               OpDecorate %3 Binding 3                                              ; 0x00000094
               OpDecorate %4 DescriptorSet 1                                        ; 0x000000a4
               OpDecorate %4 Binding 4                                              ; 0x000000b4
               OpDecorate %5 DescriptorSet 2                                        ; 0x000000c4
               OpDecorate %5 Binding 0                                              ; 0x000000d4
               OpDecorate %_runtimearr_uint ArrayStride 4                           ; 0x000000e4
               OpMemberDecorate %_struct_6 0 Offset 0                               ; 0x000000f4
               OpMemberDecorate %_struct_6 0 NonWritable                            ; 0x00000108
               OpDecorate %_struct_6 Block                                          ; 0x00000118
               OpMemberDecorate %_struct_7 0 Offset 0                               ; 0x00000124
               OpDecorate %_struct_7 Block                                          ; 0x00000138
               OpDecorate %_arr_v4uint_uint_8 ArrayStride 16                        ; 0x00000144
               OpDecorate %_arr_v4uint_uint_23 ArrayStride 16                       ; 0x00000154
               OpMemberDecorate %_struct_8 0 Offset 0                               ; 0x00000164
               OpMemberDecorate %_struct_8 1 Offset 4                               ; 0x00000178
               OpMemberDecorate %_struct_8 2 Offset 8                               ; 0x0000018c
               OpMemberDecorate %_struct_8 3 Offset 12                              ; 0x000001a0
               OpMemberDecorate %_struct_8 4 Offset 16                              ; 0x000001b4
               OpMemberDecorate %_struct_8 5 Offset 144                             ; 0x000001c8
               OpDecorate %_struct_8 Block                                          ; 0x000001dc

               ; Types, variables and constants
        %int = OpTypeInt 32 1                                                       ; 0x000001e8
      %int_5 = OpConstant %int 5                                                    ; 0x000001f8
      %float = OpTypeFloat 32                                                       ; 0x00000208
       %uint = OpTypeInt 32 0                                                       ; 0x00000214
%uint_131071 = OpConstant %uint 131071                                              ; 0x00000224
    %uint_24 = OpConstant %uint 24                                                  ; 0x00000234
     %uint_1 = OpConstant %uint 1                                                   ; 0x00000244
     %uint_0 = OpConstant %uint 0                                                   ; 0x00000254
     %uint_2 = OpConstant %uint 2                                                   ; 0x00000264
     %uint_3 = OpConstant %uint 3                                                   ; 0x00000274
     %uint_4 = OpConstant %uint 4                                                   ; 0x00000284
    %uint_32 = OpConstant %uint 32                                                  ; 0x00000294
%uint_131072 = OpConstant %uint 131072                                              ; 0x000002a4
%_runtimearr_uint = OpTypeRuntimeArray %uint                                        ; 0x000002b4, ArrayStride 4
  %_struct_6 = OpTypeStruct %_runtimearr_uint                                       ; 0x000002c0, Block
%_arr__struct_6_uint_131072 = OpTypeArray %_struct_6 %uint_131072                   ; 0x000002cc
%_ptr_StorageBuffer__arr__struct_6_uint_131072 = OpTypePointer StorageBuffer %_arr__struct_6_uint_131072    ; 0x000002dc
  %_struct_7 = OpTypeStruct %_runtimearr_uint                                                               ; 0x000002ec, Block
%_arr__struct_7_uint_131072 = OpTypeArray %_struct_7 %uint_131072                                           ; 0x000002f8
%_ptr_StorageBuffer__arr__struct_7_uint_131072 = OpTypePointer StorageBuffer %_arr__struct_7_uint_131072    ; 0x00000308
     %uint_8 = OpConstant %uint 8                                                                           ; 0x00000318
     %v4uint = OpTypeVector %uint 4                                                                         ; 0x00000328
%_arr_v4uint_uint_8 = OpTypeArray %v4uint %uint_8                                                           ; 0x00000338, ArrayStride 16
    %uint_23 = OpConstant %uint 23                                                                          ; 0x00000348
%_arr_v4uint_uint_23 = OpTypeArray %v4uint %uint_23                                                         ; 0x00000358, ArrayStride 16
  %_struct_8 = OpTypeStruct %uint %float %float %uint %_arr_v4uint_uint_8 %_arr_v4uint_uint_23              ; 0x00000368, Block
%_ptr_Uniform__struct_8 = OpTypePointer Uniform %_struct_8                                                  ; 0x00000388
     %v3uint = OpTypeVector %uint 3                                                                         ; 0x00000398
%_ptr_Input_v3uint = OpTypePointer Input %v3uint                                                            ; 0x000003a8
       %void = OpTypeVoid                                                                                   ; 0x000003b8
         %36 = OpTypeFunction %void                                                                         ; 0x000003c0
    %v3float = OpTypeVector %float 3                                                                        ; 0x000003cc
     %double = OpTypeFloat 64                                                                               ; 0x000003dc
   %v3double = OpTypeVector %double 3                                                                       ; 0x000003e8
       %bool = OpTypeBool                                                                                   ; 0x000003f8
%_ptr_Uniform_uint = OpTypePointer Uniform %uint                                                            ; 0x00000400
%_ptr_StorageBuffer__struct_6 = OpTypePointer StorageBuffer %_struct_6                                      ; 0x00000410
%_ptr_StorageBuffer_uint = OpTypePointer StorageBuffer %uint                                                ; 0x00000420
      %ulong = OpTypeInt 64 0                                                                               ; 0x00000430
          %3 = OpVariable %_ptr_StorageBuffer__arr__struct_6_uint_131072 StorageBuffer                      ; 0x00000440, DescriptorSet 1, Binding 3
          %4 = OpVariable %_ptr_StorageBuffer__arr__struct_7_uint_131072 StorageBuffer                      ; 0x00000450, DescriptorSet 1, Binding 4
          %5 = OpVariable %_ptr_Uniform__struct_8 Uniform                                                   ; 0x00000460, DescriptorSet 2, Binding 0
%gl_GlobalInvocationID = OpVariable %_ptr_Input_v3uint Input                                                ; 0x00000470, BuiltIn GlobalInvocationId
     %uint_5 = OpConstant %uint 5                                                                           ; 0x00000480


               ; Function 1
          %1 = OpFunction %void None %36                                                                    ; 0x00000490

         %46 = OpLabel                                                                                      ; 0x000004a4
         %47 =   OpLoad %v3uint %gl_GlobalInvocationID                                                      ; 0x000004ac
         %48 =   OpCompositeExtract %uint %47 0                                                             ; 0x000004bc
                 OpSelectionMerge %49 None                                                                  ; 0x000004d0
                 OpSwitch %uint_0 %50                                                                       ; 0x000004dc

         %50 =     OpLabel                                                                                  ; 0x000004e8
         %51 =       OpAccessChain %_ptr_Uniform_uint %5 %int_5 %uint_4 %uint_3                             ; 0x000004f0
         %52 =       OpLoad %uint %51                                                                       ; 0x0000050c
         %53 =       OpBitwiseAnd %uint %52 %uint_131071                                                    ; 0x0000051c
         %54 =       OpAccessChain %_ptr_StorageBuffer__struct_6 %3 %53                                     ; 0x00000530
         %55 =       OpArrayLength %uint %54 0                                                              ; 0x00000544
         %56 =       OpIMul %uint %55 %uint_4                                                               ; 0x00000558
         %57 =       OpUDiv %uint %56 %uint_24                                                              ; 0x0000056c
         %58 =       OpIAdd %uint %48 %uint_1                                                               ; 0x00000580
         %59 =       OpUGreaterThanEqual %bool %58 %57                                                      ; 0x00000594
                     OpSelectionMerge %60 None                                                              ; 0x000005a8
                     OpBranchConditional %59 %61 %60                                                        ; 0x000005b4

         %61 =         OpLabel                                                                              ; 0x000005c4
                         OpBranch %49                                                                       ; 0x000005cc

         %60 =     OpLabel                                                                                  ; 0x000005d4
         %62 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %uint_0                          ; 0x000005dc
         %63 =       OpLoad %uint %62                                                                       ; 0x000005f8
         %64 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %uint_1                          ; 0x00000608
         %65 =       OpLoad %uint %64                                                                       ; 0x00000624
         %66 =       OpUConvert %ulong %63                                                                  ; 0x00000634
         %67 =       OpUConvert %ulong %65                                                                  ; 0x00000644
         %68 =       OpShiftLeftLogical %ulong %67 %uint_32                                                 ; 0x00000654
         %69 =       OpBitwiseOr %ulong %66 %68                                                             ; 0x00000668
         %70 =       OpBitcast %double %69                                                                  ; 0x0000067c
         %71 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %uint_2                          ; 0x0000068c
         %72 =       OpLoad %uint %71                                                                       ; 0x000006a8
         %73 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %uint_3                          ; 0x000006b8
         %74 =       OpLoad %uint %73                                                                       ; 0x000006d4
         %75 =       OpUConvert %ulong %72                                                                  ; 0x000006e4
         %76 =       OpUConvert %ulong %74                                                                  ; 0x000006f4
         %77 =       OpShiftLeftLogical %ulong %76 %uint_32                                                 ; 0x00000704
         %78 =       OpBitwiseOr %ulong %75 %77                                                             ; 0x00000718
         %79 =       OpBitcast %double %78                                                                  ; 0x0000072c
         %80 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %uint_4                          ; 0x0000073c
         %81 =       OpLoad %uint %80                                                                       ; 0x00000758
         %82 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %uint_5                          ; 0x00000768
         %83 =       OpLoad %uint %82                                                                       ; 0x00000784
         %84 =       OpUConvert %ulong %81                                                                  ; 0x00000794
         %85 =       OpUConvert %ulong %83                                                                  ; 0x000007a4
         %86 =       OpShiftLeftLogical %ulong %85 %uint_32                                                 ; 0x000007b4
         %87 =       OpBitwiseOr %ulong %84 %86                                                             ; 0x000007c8
         %88 =       OpBitcast %double %87                                                                  ; 0x000007dc
         %89 =       OpCompositeConstruct %v3double %70 %79 %88                                             ; 0x000007ec
         %90 =       OpShiftRightLogical %uint %58 %uint_2                                                  ; 0x00000804
         %91 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %90                              ; 0x00000818
         %92 =       OpLoad %uint %91                                                                       ; 0x00000834
         %93 =       OpIAdd %uint %90 %uint_1                                                               ; 0x00000844
         %94 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %93                              ; 0x00000858
         %95 =       OpLoad %uint %94                                                                       ; 0x00000874
         %96 =       OpUConvert %ulong %92                                                                  ; 0x00000884
         %97 =       OpUConvert %ulong %95                                                                  ; 0x00000894
         %98 =       OpShiftLeftLogical %ulong %97 %uint_32                                                 ; 0x000008a4
         %99 =       OpBitwiseOr %ulong %96 %98                                                             ; 0x000008b8
        %100 =       OpBitcast %double %99                                                                  ; 0x000008cc
        %101 =       OpIAdd %uint %90 %uint_2                                                               ; 0x000008dc
        %102 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %101                             ; 0x000008f0
        %103 =       OpLoad %uint %102                                                                      ; 0x0000090c
        %104 =       OpIAdd %uint %90 %uint_3                                                               ; 0x0000091c
        %105 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %104                             ; 0x00000930
        %106 =       OpLoad %uint %105                                                                      ; 0x0000094c
        %107 =       OpUConvert %ulong %103                                                                 ; 0x0000095c
        %108 =       OpUConvert %ulong %106                                                                 ; 0x0000096c
        %109 =       OpShiftLeftLogical %ulong %108 %uint_32                                                ; 0x0000097c
        %110 =       OpBitwiseOr %ulong %107 %109                                                           ; 0x00000990
        %111 =       OpBitcast %double %110                                                                 ; 0x000009a4
        %112 =       OpIAdd %uint %90 %uint_4                                                               ; 0x000009b4
        %113 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %112                             ; 0x000009c8
        %114 =       OpLoad %uint %113                                                                      ; 0x000009e4
        %115 =       OpIAdd %uint %90 %uint_5                                                               ; 0x000009f4
        %116 =       OpAccessChain %_ptr_StorageBuffer_uint %3 %53 %uint_0 %115                             ; 0x00000a08
        %117 =       OpLoad %uint %116                                                                      ; 0x00000a24
        %118 =       OpUConvert %ulong %114                                                                 ; 0x00000a34
        %119 =       OpUConvert %ulong %117                                                                 ; 0x00000a44
        %120 =       OpShiftLeftLogical %ulong %119 %uint_32                                                ; 0x00000a54
        %121 =       OpBitwiseOr %ulong %118 %120                                                           ; 0x00000a68
        %122 =       OpBitcast %double %121                                                                 ; 0x00000a7c
        %123 =       OpCompositeConstruct %v3double %100 %111 %122                                          ; 0x00000a8c
        %124 =       OpFSub %v3double %123 %89                                                              ; 0x00000aa4
        %125 =       OpFConvert %v3float %124                                                               ; 0x00000ab8
        %126 =       OpAccessChain %_ptr_Uniform_uint %5 %int_5 %uint_5 %uint_0                             ; 0x00000ac8
        %127 =       OpLoad %uint %126                                                                      ; 0x00000ae4
        %128 =       OpBitwiseAnd %uint %127 %uint_131071                                                   ; 0x00000af4
        %129 =       OpCompositeExtract %float %125 0                                                       ; 0x00000b08
        %130 =       OpCompositeExtract %float %125 1                                                       ; 0x00000b1c
        %131 =       OpCompositeExtract %float %125 2                                                       ; 0x00000b30
        %132 =       OpAccessChain %_ptr_StorageBuffer_uint %4 %128 %uint_0 %90                             ; 0x00000b44
        %133 =       OpBitcast %uint %129                                                                   ; 0x00000b60
                     OpStore %132 %133                                                                      ; 0x00000b70
        %134 =       OpAccessChain %_ptr_StorageBuffer_uint %4 %128 %uint_0 %93                             ; 0x00000b7c
        %135 =       OpBitcast %uint %130                                                                   ; 0x00000b98
                     OpStore %134 %135                                                                      ; 0x00000ba8
        %136 =       OpAccessChain %_ptr_StorageBuffer_uint %4 %128 %uint_0 %101                            ; 0x00000bb4
        %137 =       OpBitcast %uint %131                                                                   ; 0x00000bd0
                     OpStore %136 %137                                                                      ; 0x00000be0
                     OpBranch %49                                                                           ; 0x00000bec

         %49 = OpLabel                                                                                      ; 0x00000bf4
                 OpReturn                                                                                   ; 0x00000bfc
               OpFunctionEnd                                                                                ; 0x00000c00

E.g. %66 = OpUConvert %ulong %63 ; 0x00000634 is emitted before working on the double, requiring the capability.

Actual Behavior
Just like DXIL don't start enabling capabilities that aren't used by the shader (DXIL only enables the 64-bit float extension rather than both).
From the D3D12 database I can't find a device that doesn't have both I64 and F64, but the vulkan database is offline so I'm not sure if any such device exists for Vulkan (for example some mobile device).

Environment

• DXC version: Ahead of latest release or the version in shader playground (2024-04-29)
• Host Operating System: N/A

[devshgraphicsprogramming]

You will find missing F64 before you find missing I64.

vulkan 1.3 onwards BDA is encouraged, and DXC doesn't even emit the uvec2 variant of BDA, so one might say that if one targets VK 1.3 int64 is very strongly implied.